On 2018-01-03, Guido van Rossum wrote:
> I'm sorry, I don't think more research can convince me either way.
> I want all three of return/break/continue to work inside finally
> clauses, despite there being few use cases.
That's fine. The history of 'continue' inside 'finally' is
interesting. The restriction dates back to at least when Jeremy
committed the AST-based compiler (I have fond memories of hacking on
it with Armin Rigo and others at a Python core sprint). Going
further back, I looked at 1.5.2 and there is the comment in
compile.c:
TO DO:
...
XXX Allow 'continue' inside try-finally
So if we allow 'continue' we will be knocking off a nearly 20 year
old todo item. ;-)
For giggles, I unpacked a Python 0.9.1 tarball. The source code is
all under 'src' in that version. There doesn't seem to be a
restriction on 'continue' but only because the grammar doesn't
include it! Without doing more research, I think the restriction
could be as old as the 'continue' keyword.
BTW, the bytecode structure for try/except shown in the compile.c
comments is very simlar to what is currently generated. It is quite
remarkable how well your initial design and implementation have stood
the test of time. Thank you for making it open source.
Regards,
Neil
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